Maybe he is too sensitive to refusals and takes it too personally?

I see that you have tried to inform him in direct manner with your pH results and he still didn't get it. Maybe there is some clever way to convince him that it doesn't have anything to do with his masculinity and that you still have desire for him but just need a break from time to time, especially when it hurts.

If it turns out that he is not capable to receive the message in any form and shape, then I'm sorry, it means your relationships won't work.